Improve sync relationship between FIM and SharePoint
I experience this issue occasionally regarding security groups that are members a SharePoint permission groups:
The sync relationship between Forefront Identity Manager (and possibly other user management applications) and SharePoint stops working for a particular security group if the display name of the SG is changed, even if the alias of the SG remains the same.
The workaround is to remove and re-add the SG to the SharePoint permission group following any updates to the SG's display name.
This issue can cause significant headaches because the people who maintain an SG are often not the same people who maintain a SharePoint site and its permission groups. It takes significant effort to keep all parties aware of the issue and ensure that they communicate display name changes.
I consider this a problem that should be fixed, not worked around indefinitely.